Electric terminal



Aug. 23, 1932. A. EDMONSON ELECTRIC TERMINAL Filed Dec. 18, 1925 i Patented Aug 23, 1932 UNITEDSTATES PATENT OFFI an'rnua EnmoNsoN, or cmvnnm, omo, assrenon T MORRIS mm, or omen, wrsoonsm 1 ELECTRIC TEBKDTAI.

Application med December 18,1925. Serial rmmasa V This invention relates to means for establishing electric connections and has a special reference to terminal connections such as those foi engagement with the terminals of storage batteries of the type generally emplo ed in automobiles.

' uch a battery is usually provided with heavy lead terminals pro ecting upwards from the battery, each of the terminals consisting of a shprt round tapered plug, the conduit to be connected therewith usually being provided with a heavy ring oflead open or split at-one side of a shank portion to I which the conduit is secured and the ring is ti htly secured upon the battery terminal by a olt passing through the ends of the ring whereby upon tightening of the bolt the ring is contracted around the terminal.

A common and serious difliculty with such an arrangement is the fact that the terminal connections are at all times subject to the fumes of the acid in which the'battery plates must be immersed, and as sulphuric acid is universally employed for this purpose the corrosive effect of the fumes is very powerful, attacking and rapidly disintegrating most metals with which they may come in contact.

Lead is the least expensive of metals having any appreciable resistance to the corrosive described and for this reason lead is commonly employed for each of the members by which these connections are made. Even lead, however, is not entirely resistant to the fumes of sulphuric acid, but forms salts upon surfaces exposed to the fumes under atmospheric conditions, which, besides weaking such a connection physically as they consume portions of the original metals, since the salts themselves are practically nonconductive of electricity and are equally liable to form and accumulate upon supposedly contacting surfaces between which the electrical connection is desired, clearly impairs the efliciency of the connection electrically as well.

One of the difficulties encountered by the use of lead is its extreme ductility and malleability. Moreover, owing to the weakness of lead a bolt of strong metal, such as steel, is required to tighten the conduit terminal upon that of the battery; and as the ferrus metals are very highly subject to thecorrosion of sulphuric acid fumes this bolt is verysoon entirely eaten away, or what is worse, just sufliciently so that the threads and heads become inoperative to either-tighten or loosen the no connection.

It is the object of this inventionto provide a novel conduit terminal connection capable of application with the present standardized battery terminal, which shall present a surface exclusively of highly acid resistant metal but which shall be of sufi'lcient strength to maintain closecontact between the terminal members whereby a minimum of corrosion can take place between the contracting sur- 05 faces, yet of such novel design as to be readily secured upon the battery terminal without the use of any tools and readily tightened, loosened and removed without the aid of any tool other than a simple wedge such as a blade of a screw driver; and yet withal shall be of a 1 very inexpensive construction.

The exact design, construction and operation of the terminal constituting my invention will be evident from reference to the following description taken in connection with the accompanying drawing in which Fig. 1 represents an end elevation of a terminal constructed according to my invention in place upon a battery terminal; Fig. 2 is a top'view of the same terminal removed from the battery terminal; Fig. 3 is a sectional view in the plane of the drawing taken through the center of Fig. 2; Fig. 4 is a section along the line 44 of Fig. 3; Fig. 5 is a view similar to that in Fig. 1 showing a means of loosening the conduit terminal from the battery terminal.

In the drawing 1 represents generally my conduit terminal, which consists of a shank portion and an open ring portion of tapered bore, the shank extending approximately tangentially from one end of the ring as appears in Figs. 2 and 3, and the whole structure aligned with a plane, as appears in Fig. 1.

The terminal is made of some acid resisting material, preferably of lead. Since lead however, is practically without strength for the purpose intended, within the ring member of the terminal I provide a stifi'ening spring member 2' as appears in Figs. 3 and 4 of highly resilient material such as SPIHIE steel and of 'suflicient size, shape and strengt to effectively support or back the comparatively large amount of the baser material, lead, with which it is surrounded. S 1nce spring'2 is sufliciently short to lie entlrely within the surrounding ring member but of such strength that the surrounding lead will be caused to conform with the spring in its resilient action, the effective resultis a resilient ring of lead. I

The shank member of the terminal'is preferably counter-bored to receive an end of the conduit 3 as appears in Fig. 3, in which bore the conduit may be soldered or burned to secure electrical and mechanical connection therebetween.

Operation of the terminal is as follows: To secure the terminal upon a battery terminal, represented by that part of Fig. 1 indicated by the reference numeral 4, the conduit terminal is placed over the battery terminal until the corresponding tapered surfaces of the two terminals are in contact. A fairly snug mechanical connection may be thus obtained between the two co-acting terminals. For the purpose of accomplishing an electrical connection however, using its shank portion as a handle the conduit terminal is next given a slight twist in a"right hand direction, as indicated by the arrow of Fig. 2. A slight tap with a light hammer may be given to the shank in the position and direction of the arrow referred to, where an exceptionally good contact is required, aswhere a large current flow is anticipated, meanwhile maintaining a slight downward pressure of the conduit terminal upon the battery terminal.

This motion, owing to the wedging effect of the battery terminal within the ring of the conduit terminal, the binding friction between the contacting surfaces, and the direction of the leverage of the shank portion of the conduit terminal somewhat spreads the ring against the action of the spring, and

seats thering about the battery terminal with a force sufiicient to overcome slight irregularities in the soft lead surfaces; and the strength of the spring 2 is sufiicient to maintain the perfect physical and electrical connection thus obtained between the parts.

Thereafter a tap or other force upon the shank but in the opposite or left hand direction effectively locks the terminal in seated position.

To disconnect the terminals, the conduit terminal is given a slight twist in the opposite direction, as by again using the shank portion as a handle, or by a slight tap upon the shank in the direction of the downward ly pointed arrow, when both the friction between the surfaces and the leverage of the shank tend to free the contacting surfaces, and owing to the taper the surfaces are loosactual scope of the invention as defined in the following claims:

What I claim is:

1. A cable terminal adapted to establish connection with a conical storage-battery post, said terminal comprising a split ring portion of soft non-corrosive metal having its opening tapering to receive the battery post, said portlon being made resilient by a stiffening spring therewithin and surround ed by a substantial thickness of said soft metal, said terminal having a shank portion extending from one end of said ring portion, whereby, when said terminal is fitted over a battery post, movement of the terminal thereabout in one direction will tighten the fit and in the other direction will loosen the fit, when said movement is produced by forces applied through said terminal shank portion as a handle.

2. A cable terminal adapted to establish connection with a conical storage battery post, said terminal comprising a ring portion of soft non-corrosive metal having its opening tapered to receive the battery post, and

said shank portion in a plane nonradial of the rin and the ring being made resilient by a sti ening spring surrounded by a substantial thickness of said soft metal, whereby, when said terminal is fitted over a battery post, movement of the terminal thereabout in one direction will tighten the fit and in the other direction will loosen the fit, when said movement is provided by forces applied throu h the shank portion as a handle.

.3. 1% heavy duty battery terminal comprising an open ended member made of sprin material havin considerable resiliency, sai member including a battery terminal engaging portion having a substantiall circular opening into which a battery termmal is received, said opening being, when the battery terminal engaging portion is in normal position, of a smaller diameter than the battery terminal which is to be received thereinto so that the spring material alone will cause the battery terminal engaging portion to engage the battery terminal with sufficient pressure to make a good electrical connection, the open ends of said member being in relatively close proximity to each other and having opposed tool-engaging surfaces, whereby said portion may, by separating the ends, be iiexed to cause the opening therem to become larger than the battery terminal so that the terminal may be inserted into said 0 ning, said member being coated with an aci resisting sheath.

4. A heavy duty battelgeterminal comprising an open ended mem r made of spring material havin considerable resiliency, said member including a battery terminal engaging portion having a substantially circular opening into which a battery terminal is received, said opening being, when the battery terminal engagm portion is in normal position, of a smaller iameter than the battery terminal which is to be received thereinto so that the sprin material alone will cause the battery terminal engaging portion to engage the battery terminal with sufiicient pressure to make a goodelectrical connection, the open ends of said member being in relatively close proximity to each other, and having opposed tool-engaging surfaces, whereby said portion may, by separating the ends, be flexe to cause the opening therein to become larger than the battery terminal so that the terminal may be inserted into said 0 Tait; member being coated with a layer of In testimony whereof I hereby aflix my.

signature.

ARTHUR EDMONSON. 

